API: Enforce annual limits

[andrewleith]

API

API endpoints

• Prevent sending bulk When service is at its limit, or send would put them over
• Prevent sending one-off when service is at its limit

Admin endpoints

• Prevent sending bulk When service is at its limit, or send would put them over
• Prevent sending one-off when service is at its limit

[yaelberger-commits]

Please add your planning poker estimate with Zenhub @whabanks

[yaelberger-commits]

Will working on writing tests and then will put up PR. Jumana's task today is dependent on this PR

[whabanks]

Finished the validator code to unblock Jumana's work with email sending. Added validation logic on our sending paths - nearly finished writing tests for this and validation will be complete.

[amazingphilippe]

Finished some PRs yesterday. Looking to create a release. Moving to review.

[whabanks]

Merging final PR's and beginning testing in staging today.